Eightfold functionalized octasilsesquioxanes (R(8)Si(8)O(12)) are synthesized using the hydrosilylation method. Different types of groups R, consisting of an (-O-SiMe(2)(CH2)(2)) spacer unit and various terminal units (-CH2(C(2)Me)B10H10, -C(5)H(3)MeMn(CO)(3), -SiMe(2)C(5)H(4)FeC(5)H(5), -SiMeCl(2) -SiMeCl(2), -Si(OEt)(3)) have been introduced. The hydrosilylation products have been characterized by H-1: C-13, Si-29 NMR and infrared spectroscopy and elemental analysis. The redox properties of the ferrocenyl substituted compound have been studied by cyclovoltammetry.